Dual photon (or x-ray) energy absorptionmetry projection techniques--also referred to as DPA, DPX or DEXA--have been used for the measurement of bone mineral density and total body composition in patients. Most commonly, total body bone mineral is calculated with full body scans to measure the effects of osteoporosis, for example. Although DEXA enables some level of soft tissue discrimination, the photon energies used are generally too high for doing non mineralogical types of body analysis.